Ralph Kothe

Biomechanical analysis of transpedicular screw fixation in the subaxial cervical spine.

Study Design. An in vitro biomechanical study to compare 2 different dorsal screw fixation techniques in the cervical spine with respect to primary stability and stability after cyclic loading. Objectives. To investigate if the biomechanical stability is better in pedicle screw or in lateral mass fixation. Summary of Background Data. In patients with poor bone quality who require multisegmental fixations, the current dorsal stabilization procedures in the subaxial cervical spine using lateral mass screws are often insufficient. Cervical pedicle screw fixation has been suggested as an alternative procedure, but there are still limited data available on the biomechanical differences between pedicle screw and lateral mass fixation. Methods. A severe multilevel discoligamentous instability was created in 8 human cervical spine specimens (C2–C7). Dorsal stabilization was performed with the assistance of computer navigation (SurgiGate, Medivison, Switzerland) using either lateral mass or pedicle screw fixation. In the first part of the study, primary stability was measured by means of a multidirectional flexibility test. Then, specimens were divided into 2 groups, randomized for bone mineral density. Cyclic loading was applied with sinusoidal loads in flexion/extension (1000 cycles, ±1.5 Nm, 0.1 Hz). Mechanical behavior of the specimens was determined by a flexibility test before and after the application of cyclic loads. Data analysis was performed by calculating the ranges of motion, and statistical differences were determined with the t test for group comparison. Results. Pedicle screw fixation showed a significantly higher stability in lateral bending (pedicle screw range of motion 0.86 ± 0.31°; lateral mass range of motion 1.43 ± 0.62°; P = 0.037). No significant differences were seen in flexion/extension and axial rotation. After cyclic loading, the decrease in stability was less with pedicle screw fixation in all load directions. Differences in the decrease of stability were statistically significant in flexion/extension (pedicle screw 95.4 ± 9.4%; lateral mass 70.5 ± 9.8%; P = 0.010) and lateral bending (pedicle screw 105.3 ± 5.0%; lateral mass 84.2 ± 13.6%; P = 0.046), whereas there was no significant difference in axial rotation. Conclusions. The major finding of the current study was the higher stability of pedicle screws over lateral mass fixation with respect to primary stability and stability after cyclic loading. From a biomechanical point of view the use of pedicle screws in the subaxial cervical spine seems justified in patients with poor bone quality and need for multisegmental fixation.

Internal architecture of the thoracic pedicle. An anatomic study.

Study Design In this study, data are presented that provide the surgeon with additional information about the internal structure of the thoracic pedicle, which is especially useful for pedicle screw fixation in the thoracic spine. Objectives To quantify the internal structure of the pedicle in the thoracic spine. Summary of Background Data There are many studies describing the external dimensions of the thoracic pedicle (i.e., pedicle height, pedicle width, and pedicle axis in the transverse and sagittal planes). However, there is little reliable information concerning the internal structure of the pedicle. Methods Eighteen thoracic vertebrae were attached to a thin-sectioning machine and both pedicles were cut in six 1.0-mm thin slices. Slides of contact radiographs were rear-projected to a digitizer and the internal and external borders of the pedicle were digitized. Using special computer software, two external dimensions (i.e., pedicle height and pedicle width) and four internal dimensions (i.e., cortical thicknesses of the superior, inferior, medial, and lateral walls) were calculated. Results The cancellous core was more than twice as large as the cortical shell, with a range from 65.6% to 78.6% with respect to the pedicle height, and 61.3% to 71.6% with respect to the pedicle width. The medial wall was between two and three times thicker than the lateral wall throughout all the pedicle slices and thoracic levels. These differences were highly significant (P < 0.001). Conclusions The thoracic pedicle is a complex three-dimensional structure that is mostly filled with cancellous bone. The medial wall is significantly thicker than the lateral wall, which could explain the fact that most of the pedicle fractures related to pedicle screw insertion occur laterally.

Clinical evaluation and computed tomography scan analysis of screw tracts after percutaneous insertion of pedicle screws in the lumbar spine

STUDY DESIGN An examination of the accuracy of percutaneous pedicle screw placement in the lumbar spine. Using computed tomography scan analysis after implant removal, the screw tracts could be analyzed regarding the degree and direction of screw dislocation. OBJECTIVES To investigate the misplacement rate and related clinical complications of percutaneous pedicle screw insertion in the lumbar spine. SUMMARY OF BACKGROUND DATA The feasibility of the external fixation test has been investigated in several studies. Although pedicle screw misplacement has been reported as one of the main complications, there are no reliable data on the misplacement rate for this difficult surgical procedure. METHODS In this study, 51 consecutive patients with suspected segmental instability were investigated after external transpedicular screw insertion for the external fixation test. Computed tomography scans of all instrumented pedicles from L2 to S1 were performed after screw removal. The screw tracts were analyzed, and the direction and degree of the pedicle violations were noted. In addition, the screw and pedicle angles were measured. RESULTS Of 408 percutaneously inserted pedicle screws, only 27 screws (6.6%) were misplaced. There were 19 medial pedicle violations, 6 lateral cortical defects, and only 1 cranial and 1 caudal displacement. With respect to the spinal level, S1 showed the highest misplacement rate, with 11 screw dislocations (12%). After surgery, found two nerve root injuries were found. Only one of the injuries (L4) was related to the malposition of a screw. CONCLUSIONS This study has shown that percutaneous insertion of pedicle screws in the lumbar spine is a safe and reliable technique. Despite the low misplacement rate of only 6.6%, it should be kept in mind that the surgical procedure is technically demanding and should be performed only by experienced spine surgeons.

Growth Changes of Solidly Fused Kyphotic Bloc After Surgery for Tuberculosis: Comparison of Four Procedures

Study Design. A study to analyze the changes of the spinal deformity during the growth period, with regard to different operations for spinal tuberculosis in children. Objectives. To quantify the changes in the kyphotic angle and the growth ratio of the fusion bloc during spinal growth for different fusion techniques. Summary of Background Data. Most of the publications dealing with spinal tuberculosis in children focused on the clinical outcome with regard to different conservative and operative treatments. There is little reliable information concerning the growth of the solidly fused kyphotic bone bloc and its influence on the changes of the kyphotic deformity after different operative procedures. Methods. The study included 117 children operated on for spinal tuberculosis at the age of 2‐6 years at the Ruttonjee Sanatorium in Hong Kong during the 1950s and 1960s. Lateral radiographs obtained postoperatively and 5 and 10 years after the operation were analyzed for the growth changes of the solidly fused bone bloc. These results were compared with the different operation techniques (e.g., anterior fusion, posterior fusion, combined anterior and posterior fusion, and anterior debridement without fusion). Results. The patients treated by anterior fusion showed the worst results with respect to the kyphotic angle. This was especially true when the lesion was located in the thoracic spine and several segments were involved. Regarding the growth ratio of the fusion bloc, only the combined fusion and the anterior debridement guaranteed an equal growth of the anterior and posterior height. Conclusions. Radical anterior surgery for spinal tuberculosis destroys the anterior growth and limits the capacity for spinal remodeling. Therefore, it should be avoided, if it is not absolutely necessary, for the healing of the infection or the primary correction of the tuberculous deformity.

Multidirectional instability of the thoracic spine due to iatrogenic pedicle injuries during transpedicular fixation: A biomechanical investigation

Study Design. Pedicle fracture was simulated in an in vitro model, and its effect on multidirectional stability provided by pedicle instrumentation was quantified. Objectives. To quantify the multidirectional flexibility of pedicle instrumentation due to different iatrogenic pedicle injuries. Summary of Background Data. Misplacement of the screw and iatrogenic pedicle fracture are the main complications of pedicle instrumentation. Despite the increasing number of clinical studies dealing with this issue, there is little reliable information concerning the biomechanical effects of an intraoperative pedicle fracture. Methods. A burst fracture was created in 10 human cadaveric five‐vertebrae spine specimens, from the middle and lower thoracic spine regions. The fracture was stabilized with a semirigid pedicle screw fixation device. To simulate an intraoperative pedicle fracture, the pedicles of the instrumented segments were resected in four steps. After each pedicle injury, three‐dimensional flexibility in the form of range of motion and neutral zone of the construct was determined and compared with the intact values. Results. Resection of the pedicles had little effect on the multidirectional flexion‐extension stability provided by the instrumentation. There were significant increases of axial rotation in the middle thoracic spine when the lateral wall was resected (range of motion, 8.2° vs. 3.6°; neutral zone, 4.2° vs. 1.7°), whereas in the lower thoracic spine, significant increases occurred only when all the pedicles were resected (range of motion, 3.8° vs. 1.4°; neutral zone, 1.1° vs. 0.4°). Lateral resection of the pedicle resulted in significant increases of range of motion and neutral zone for lateral bending in both the middle thoracic spine (range of motion, 19.0° vs. 10.0°; neutral zone, 2.4° vs. 1.1°) and the lower thoracic spine (range of motion, 4.3° vs. 2.5°; neutral zone, 0.9° vs. 0.3°). Conclusions. Resection of the pedicles results in a significant decrease in axial rotation and lateral bending stability provided by the instrumentation. This effect was higher in the middle than in the lower thoracic spine and may be relevant to pedicle fractures produced by pedicle screws used in these regions.

Computer navigation of parapedicular screw fixation in the thoracic spine: a cadaver study.

Study Design. An in vitro study to investigate the advantages of computer assistance for the purpose of parapedicular screw fixation in the upper and middle thoracic spine. Objectives. To evaluate the feasibility and application accuracy of parapedicuar screw insertion with the assistance of an optoelectronic navigation system. Summary of Background Data. Because of anatomic limitations, thoracic pedicle screw insertion in the upper and middle thoracic spine remains a matter of controversy. The technique of parapedicular screw insertion has been described as an alternative, although the exact screw position is difficult to control. With the assistance of computer navigation for the screw placement, it might become possible to overcome these challenges. Methods. Four human specimens were harvested for this study; 6-mm screws were inserted from T2 to T8 with the assistance of a CT-based optoelectronic navigation system. During surgery virtual images of the screw position were documented and compared with postoperative contact radiographs to determine the application accuracy. The following measurements were obtained: axial and sagittal screw angles as well as the screw distances to the anterior vertebral cortex and the medial pedicle wall. Results. All 54 screws were inserted in a parapedicular technique without violation of the medial pedicle wall or the anterior or lateral vertebral cortex. The mean ± standard deviation difference between the virtual images and the radiographs was 1.0 ± 0.94 mm for the distance to the medial pedicle wall and 1.9 ± 1.44 mm for the distance to the anterior cortex. The angular measurements showed a difference of 1.6 ± 1.1° for the transverse screw angle and 2.1 ± 1.6° for the sagittal screw orientation. Conclusion. With the assistance of computer navigation it is possible to achieve a safe and reliable parapedicular screw insertion in the upper and middle thoracic spine in vitro. The application accuracy varies for the linear and angular measurements and is higher in the axial than in the sagittal plane. It is important for the surgeon to understand these limitations when using computer navigation in spinal surgery.

Rheumatoid arthritis of the cervical spine. Current concepts for diagnosis and therapy

The involvement of the cervical spine in patients with rheumatoid arthritis (RA) is common,and has recently received growing attention. In the early stage of the disease, there is an isolated atlantoaxial subluxation (AAS). With further progression, osseous destruction of the joints can lead to vertical instability. While the involvement of the middle and lower cervical spine can cause a subaxial instability, neurological deficits can occur at any time. The onset of cervical myelopathy in patients with RA is often missed because of additional problems related to the hands and feet. If patients show clear symptoms of cervical myelopathy, the progression of the disease cannot be stopped by conservative treatment. Other indications for operative treatment are severe pain and radiological evidence of progressive instability. In the case of an isolated AAS, fusion can be restricted to the C1/C2 segment. If there is evidence for vertical or subaxial instability, an occipitocervical fusion has to be performed. To avoid instability adjacent to the fusion, the surgeon must check for signs of potential subaxial instability. If this is the case, fusion should include the entire cervical spine. Additional transoral decompression may be necessary when there is persistent retrodental pannus or osseous compression by an irreducible transverse dislocation or cranial migration of the dens. Non-ambulatory myelopathic patients are more likely to present severe surgical complications with limited prospects of functional recovery. Therefore, it is important to avoid the development of severe cervical myelopathy by early surgical intervention.ZusammenfassungDie Beteiligung der Halswirbelsäule (HWS) im Rahmen der rheumatoiden Arthritis (RA) ist häufig und hat zunehmend an Bedeutung gewonnen. Am Anfang steht dabei meist die isolierte atlantoaxiale Subluxation. Durch eine knöcherne Destruktion der Gelenke kann es zu einer vertikalen Instabilität kommen. Eine Beteiligung der mittleren und unteren HWS wird als subaxiale Instabilität bezeichnet. Neurologische Störungen können zu jedem Zeitpunkt der Erkrankung auftreten. Der Beginn der zervikalen Myelopathie wird beim Rheumatiker aufgrund der zusätzlichen Manifestationen an Händen und Füßen leider häufig übersehen.Hat sich eine Myelopathie bereits klinisch eindeutig manifestiert, so ist der weitere progressive Verlauf mit konservativen Mitteln nicht mehr aufzuhalten.Eine Operationsindikation besteht neben der beginnenden Myelopathie auch bei therapierefraktären Schmerzzuständen, sowie dem radiologischen Nachweis einer progredienten Instabilität. Im Falle einer isolierten atlantoaxialen Subluxation kann die Fusion auf dieses Segment beschränkt werden,was häufig einer weiteren rheumatischen Destruktion der HWS vorbeugt.Im Falle einer vertikalen Instabilität oder einer subaxialen Beteiligung ist eine kraniozervikale Fusion notwendig.Dabei sollte präoperativ sorgfältig nach einer potentiellen subaxialen Instabilität gefahndet werden. Lässt sich eine solche nachweisen, ist die Fusion auf die gesamte HWS auszudehnen. Im Falle einer anhaltenden Weichteilkompression oder knöchernen ventralen Raumforderung ist gelegentlich eine zusätzliche transorale Dekompression notwendig. Besteht bereits eine fortgeschrittene neurologische Schädigung mit Verlust der Gehfähigkeit erhöhen sich die perioperative Morbidität und Mortalität erheblich.Das vorrangige Ziel des betreuenden Arztes sollte deshalb die Vermeidung solcher fortgeschrittenen zervikalen Destruktionen sein. Dies ist jedoch nur durch eine rechtzeitige und konsequente operative Behandlung möglich.AbstractThe involvement of the cervical spine in patients with rheumatoid arthritis (RA) is common,and has recently received growing attention. In the early stage of the disease, there is an isolated atlantoaxial subluxation (AAS). With further progression, osseous destruction of the joints can lead to vertical instability. While the involvement of the middle and lower cervical spine can cause a subaxial instability, neurological deficits can occur at any time. The onset of cervical myelopathy in patients with RA is often missed because of additional problems related to the hands and feet. If patients show clear symptoms of cervical myelopathy, the progression of the disease cannot be stopped by conservative treatment.Other indications for operative treatment are severe pain and radiological evidence of progressive instability. In the case of an isolated AAS, fusion can be restricted to the C1/C2 segment. If there is evidence for vertical or subaxial instability, an occipitocervical fusion has to be performed.To avoid instability adjacent to the fusion, the surgeon must check for signs of potential subaxial instability. If this is the case, fusion should include the entire cervical spine. Additional transoral decompression may be necessary when there is persistent retrodental pannus or osseous compression by an irreducible transverse dislocation or cranial migration of the dens. Non-ambulatory myelopathic patients are more likely to present severe surgical complications with limited prospects of functional recovery. Therefore, it is important to avoid the development of severe cervical myelopathy by early surgical intervention.

Therapie der zervikalen rheumatoiden Arthritis

Zusammenfassung.Der rheumatische Befall der Halswirbelsäule kann in drei Stadien eingeteilt werden. Am Anfang steht zumeist die isolierte atlantoaxiale Subluxation (AAS), gefolgt von der vertikalen Instabilität und der subaxialen Instabilität. Eine zervikale Myelopathie kann dabei in jedem Stadium der rheumatischen Destruktion auftreten. Bei klinisch manifester Myelopathie ist der weitere progressive Verlauf ohne Operation nicht mehr aufzuhalten. Insbesondere zu Beginn der Erkrankung hat die konservative Therapie einen hohen Stellenwert. Neben der Patientenaufklärung ist durch die Ruhigstellung mittels Halskrawatte, sowie eine gezielte Physiotherapie eine Besserung der Schmerzsymptomatik zu erwarten. Eine frühzeitige und effektive DMARD-Medikation kann zu einer positiven Beeinflussung des natürlichen Krankheitsverlaufes führen. Bei progredienter Instabilität, beginnender Myelopathie oder therapierefraktären Beschwerden ist eine operative Behandlung indiziert. Eine atlantoaxiale Fusion sollte bei isolierter AAS durchgeführt werden. Operationsmethode der Wahl ist die transartikuläre Verschraubung nach Magerl. Bei Nachweis einer vertikalen Instabilität oder fortgeschrittener Destruktion der C0/C1-Gelenke ist eine kraniozervikale Fusion notwendig. Dabei sollte präoperativ nach einer potentiellen subaxialen Instabilität gesucht werden. Bei positivem Nachweis ist die Fusion auf die gesamte HWS auszudehnen. Eine transorale Dekompression ist nur bei anhaltender ventraler Myelonkompression notwendig, was typischerweise bei der fixierten AAS der Fall ist. Besteht bereits eine fortgeschrittene neurologische Schädigung mit Verlust der Gehfähigkeit erhöhen sich die perioperative Morbidität und Mortalität erheblich. Solche fortgeschritten Stadien der komplexen zervikalen Destruktion sollten deshalb durch eine frühzeitige operative Behandlung vermieden werden. Die Wahl des richtigen Operationszeitpunktes ist allerdings weiterhin umstritten. Zukünftige prospektiv, randomisierte Studien müssen deshalb diese Fragestellung aufgreifen, damit die Therapiekonzepte für die rheumatische HWS verbessert werden können.Summary.The rheumatoid involvement of the cervical spine can be divided into three phases. In the early stage of the disease there is an isolated atlantoaxial subluxation (AAS), followed by vertical instability and subaxial instability. If patients show clear symptoms of cervical myelopathy, which can occur during any stage of the disease, the progression cannot be stopped by conservative treatment, which is of great importance at the beginning of the cervical manifestation. Patient education, physiotherapy and immobilization with a stiff collar can significantly reduce pain. Early and effective DMARD therapy can have a positive effect on the natural history of the disease. In case of progressive instability, cervical myelopathy or severe pain operative treatment is indicated. If there is an isolated AAS, fusion can be restricted to the C1/C2 segment. The Magerl transarticular screw fixation is the preferred technique for stabilization. If there is evidence for vertical instability or severe destruction of the C0/C1 joints, occipital cervical fusion has to be performed. Durin the preoperative planning it is necessary to look for signs of subaxial instability. If this is the case, fusion should include the entire cervical spine. Transoral decompression may be necessary when there is persistent anterior compression of the myelon, typically seen in fixed AAS. Non-ambulatory myelopathic patients are more likely to develop severe surgical complications. Therefore, it is important to avoid the development of severe cervical instability by early surgical intervention. The right timing for surgery is still a matter of controversy. Future prospective randomized trials should address this topic to improve the treatment concept for the rheumatoid patient.

Therapy of cervical rheumatoid arthritis

Zusammenfassung.Der rheumatische Befall der Halswirbelsäule kann in drei Stadien eingeteilt werden. Am Anfang steht zumeist die isolierte atlantoaxiale Subluxation (AAS), gefolgt von der vertikalen Instabilität und der subaxialen Instabilität. Eine zervikale Myelopathie kann dabei in jedem Stadium der rheumatischen Destruktion auftreten. Bei klinisch manifester Myelopathie ist der weitere progressive Verlauf ohne Operation nicht mehr aufzuhalten. Insbesondere zu Beginn der Erkrankung hat die konservative Therapie einen hohen Stellenwert. Neben der Patientenaufklärung ist durch die Ruhigstellung mittels Halskrawatte, sowie eine gezielte Physiotherapie eine Besserung der Schmerzsymptomatik zu erwarten. Eine frühzeitige und effektive DMARD-Medikation kann zu einer positiven Beeinflussung des natürlichen Krankheitsverlaufes führen. Bei progredienter Instabilität, beginnender Myelopathie oder therapierefraktären Beschwerden ist eine operative Behandlung indiziert. Eine atlantoaxiale Fusion sollte bei isolierter AAS durchgeführt werden. Operationsmethode der Wahl ist die transartikuläre Verschraubung nach Magerl. Bei Nachweis einer vertikalen Instabilität oder fortgeschrittener Destruktion der C0/C1-Gelenke ist eine kraniozervikale Fusion notwendig. Dabei sollte präoperativ nach einer potentiellen subaxialen Instabilität gesucht werden. Bei positivem Nachweis ist die Fusion auf die gesamte HWS auszudehnen. Eine transorale Dekompression ist nur bei anhaltender ventraler Myelonkompression notwendig, was typischerweise bei der fixierten AAS der Fall ist. Besteht bereits eine fortgeschrittene neurologische Schädigung mit Verlust der Gehfähigkeit erhöhen sich die perioperative Morbidität und Mortalität erheblich. Solche fortgeschritten Stadien der komplexen zervikalen Destruktion sollten deshalb durch eine frühzeitige operative Behandlung vermieden werden. Die Wahl des richtigen Operationszeitpunktes ist allerdings weiterhin umstritten. Zukünftige prospektiv, randomisierte Studien müssen deshalb diese Fragestellung aufgreifen, damit die Therapiekonzepte für die rheumatische HWS verbessert werden können.Summary.The rheumatoid involvement of the cervical spine can be divided into three phases. In the early stage of the disease there is an isolated atlantoaxial subluxation (AAS), followed by vertical instability and subaxial instability. If patients show clear symptoms of cervical myelopathy, which can occur during any stage of the disease, the progression cannot be stopped by conservative treatment, which is of great importance at the beginning of the cervical manifestation. Patient education, physiotherapy and immobilization with a stiff collar can significantly reduce pain. Early and effective DMARD therapy can have a positive effect on the natural history of the disease. In case of progressive instability, cervical myelopathy or severe pain operative treatment is indicated. If there is an isolated AAS, fusion can be restricted to the C1/C2 segment. The Magerl transarticular screw fixation is the preferred technique for stabilization. If there is evidence for vertical instability or severe destruction of the C0/C1 joints, occipital cervical fusion has to be performed. Durin the preoperative planning it is necessary to look for signs of subaxial instability. If this is the case, fusion should include the entire cervical spine. Transoral decompression may be necessary when there is persistent anterior compression of the myelon, typically seen in fixed AAS. Non-ambulatory myelopathic patients are more likely to develop severe surgical complications. Therefore, it is important to avoid the development of severe cervical instability by early surgical intervention. The right timing for surgery is still a matter of controversy. Future prospective randomized trials should address this topic to improve the treatment concept for the rheumatoid patient.

Morphologische Diagnostik von WirbelsäulenerkrankungenDerzeitige technische Möglichkeiten und Anforderungen an die histologische Bearbeitung von transpedikulär entnommenen Biopsien

ZusammenfassungDie Wirbelsäule ist das zentrale Organ für alle Bewegungsabläufe des menschlichen Organismus. Sowohl lokal begrenzte als auch diffuse Erkrankungen der Wirbelsäule stellen aufgrund der komplizierten topographischen Verhältnisse den behandelnden Arzt im Einzelfall vor erhebliche Probleme. Mit einer bioptischen Untersuchung eines pathologisch veränderten Wirbelkörpers lässt sich schnell und zuverlässig eine Diagnose als Basis für die weitere Therapie stellen. Die Biopsie als diagnostisches Standardverfahren bei Erkrankungen der Wirbelsäule ist allerdings bisher nur begrenzt angewendet worden, da häufig stark mikrofrakturiertes Gewebe aufgrund der komplizierten anatomischen Verhältnisse gewonnen wurde. Die eigenen Erfahrungen mit transpedikulären Wirbelkörperbiopsien bei 70 Patienten mit sehr unterschiedlichen Erkrankungen sollen daher aufgrund der erheblich verbesserten Biopsietechnik und den methodischen Möglichkeiten in der Bearbeitung von Knochengewebe mitgeteilt werden. Methodisch besonders bewährt haben sich die Anfertigung von Kontaktradiographien der Biopsien, die Durchführung einer schonenden EDTA-Entkalkung sowie die Kunststoffeinbettung und die Anwendung immunhistologischer Verfahren. Auf diese Weise können in 97% der Fälle eindeutige Diagnosen gestellt werden. Es wird daher empfohlen, eine enge Kooperation mit dem biopsierenden Kliniker zu suchen und einen höheren methodischen Einsatz als die alleinige “Schnellentkalkung” zu betreiben.AbstractThe spine is the central component for the mobility of the human body. Both locally limited and diffuse pathologies of the spine are a challenge for the treating physician due to the difficult anatomy. The biopsy of a pathologically altered vertebral body is a fast and reliable basis for further therapy but until now this has not regularly been made use of as a diagnostic standard for spinal diseases, since the tissue gained was often microfractured because of the difficult anatomical position. Our own experience with transpedicular vertebral biopsies of 70 patients with different diseases is reported because of the considerable improvement in the biopsy technique and the methodical possibilities for processing the bony tissue. Methods which have proven particularly valuable are contact radiographs, embedding in plastic, careful decalcifying with EDTA and immunhistological procedures. In this way a definite diagnosis can be made in 97% of the cases. A close cooperation with the clinician carrying out the biopsy and a greater use of methods other than just fast decalcification is recommended.